1 Department of General Practice and Health Services Research, University Hospital Heidelberg, Heidelberg D-69120, Germany. Electronic address: kayvan.bozorgmehr@med.uni-heidelberg.de.
2 Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany; Division of Clinical Epidemiology and Ageing Research, German Cancer Research Centre, Heidelberg, Germany.
3 Public Health Authority, Pforzheim/Enzkreis, Germany.
4 Department of Epidemiology and International Public Health, School of Public Health, Bielefeld University, Bielefeld, Germany.